The present invention relates to an apparatus having a hand shaft formed of synthetic resin, on which a hand is mounted.
A typical conventional hand shaft for use in an analog watch is disclosed, for example, in U.S. Pat. No. 3,979,901. A second wheel for moving a second hand is rotatably supported on a main plate, and its shaft portion is disposed rotatably in the cylindrical shaft portion of the center wheel. In this apparatus, the shaft portion of the second wheel must have high strength, because a strong force is applied when the second hand is mounted thereto. Thus, the second wheel is, heretofore, made of metal. In the second wheel formed of the metal, a plurality of projections are formed at a part of the shaft portion of the second wheel so as to contact the inner surface of the cylindrical shaft portion of the center wheel and oil is coated on the projections to reduce the frictional resistance between the shaft portion of the second wheel and the inner surface of the cylindrical shaft portion of the center wheel. Forming the projections on the shaft portion of the second wheel causes the structure of the second wheel to be complicated so that the working becomes troublesome and the cost becomes high.
Recently, the gears of the watch have been formed of synthetic resin. Thus, it is tried to form the shaft portion of the second wheel, on which a second hand is mounted, of synthetic resin in a conventional process, but since the diameter of the shaft portion is very small, the shaft portion might sometimes be deformed or damaged when the hand is press-fitted to the shaft portion.